DE2531566A1 - COMBUSTION MACHINE WITH INTERNAL COOLING OF THE COMBUSTION CHAMBER - Google Patents

Description

. ♦ »t 2531568

Patent attorney

irg. G. VJclahsason

-S Munich 22 chicken, the '' '"l'

Widenmayt-rstrasse 46 T 38P

Tel. (O8S) 29 5125

TOWMSEND ENGINEERING COMPANY in Des Moines, Iowa / V.St.A.

Internal combustion engine with internal cooling of the combustion chamber

The invention relates to an internal combustion engine with internal cooling of the combustion chamber by excess purge air.

In the known internal combustion engines, the heat of the explosion is partly through the walls of the surrounding metal parts and then blasted into the air by means of ribs on the outer surface of the cylinder or by a cooling liquid discharged. These known internal combustion engines are largely well designed; however, it was found that the efficiency can still be improved if the heat of combustion is prevented from the outset from absorbed by the cylinder, the piston and the remaining parts of the combustion chamber.

It has been proposed to add the combustion chamber to this corner to cool from the inside by after each work cycle

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excess purge air is introduced into the cylinder. This relatively cool fresh air is therefore not used only, as is known, to blow out the combustion gases, but also to remove the heat generated during combustion before it is picked up by the metal parts around the combustion chamber and discharged to the outside.

The invention specified in the characterizing part of claim 1 is based on the object in such an internal combustion engine to reduce the heat transfer to the walls of the combustion chamber even further and thereby a greater one Part of the heat of combustion to be dissipated through the excess purge air.

This is achieved according to the invention in that the combustion chamber is at least partially lined with a poorly thermally conductive material. B. serve a ceramic material or stainless steel.

It is also possible to completely remove the cylinder. And the piston made of a material with a low coefficient of thermal conductivity to manufacture.

The measures according to the invention result in a Internal combustion engine that is economical to manufacture and is robust in operation and has an improved degree of efficiency.

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The invention is described below with reference to the drawing. Are in it

1 shows a perspective illustration of an exemplary embodiment of the internal combustion engine according to the invention,

Fig. 2 is a section in the direction of the line 2-2 in Fig. 1 with broken away parts in a larger hatred,

3 shows a perspective illustration of a cylinder, FIG. 4 shows a partial illustration of FIG. 2 on a larger scale,

FIG. 5 shows a representation corresponding to FIG. 4, but for a different embodiment,

Fig. 6 is a partial section, seen along the line 6-6 in Fig. 1 with parts broken away;

Figure 7 is a longitudinal section of the fixed core part of the machine

and
FIG. 8 shows a sectional illustration in the direction of the line 8-8 in FIG. 6.

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The machine shown is generally designated 10 and has two shell halves 12 and 14, which with screws 16 are held together. A circular cam disk 18 is clamped between the shell halves 12 and 14, The cam 18 engages in annular grooves 2o and 22 of the shell halves 12 and 14 (FIG. 6). On the shell half 12, a foot part 24 is also attached.

A drive shaft 26 protrudes inward through the shell half 12 and is supported there in a main bearing 28. Of the Shell half 14 is opposite to the drive shaft a stationary core 30, the end face 32 of which is close to the inner one End of the drive shaft 26 is arranged. The core 30 consists of the parts 34 and 36 which are held together with screws 38 will. Recesses 40 and 42 are provided on opposite sides of the core part 34, as in FIG. 7 shows. The core 30 is provided with an oil feed 44 for supplying the annular grooves 46 and 48 attached to its circumference provided with lubricating and sealing oil.

The core part 36 also has an internally threaded opening 50 to which a hose 52 for supplying Compressed air is connected. The opening 50 is in communication with an air chamber 54, one of which is longitudinally The core extending channels 56 and 58 go out. Channels 56 and 58 settle in corresponding channels 60 and 62

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of the core part 34. These channels 60 and 62 end in the Recesses 42 and 40 in air outlet openings 64 and 66. Finally, a needle valve 68 is located in the core 30, by means of which fuel is supplied to the injection nozzles 70 and 72 at certain time intervals.

The core 34 carries a rotor 74 as described in U.S. Patent 3,828. The peripheral part 76 of the rotor 74 is four circular recesses 78 provided. The hub portion 80 of the rotor 74 is attached to the shaft 26. In every recess 28 is a cylinder 82, the flange part 84 of which rests on the rotor and with screws, which by corresponding Holes 86 of the flange 84 go, is attached to the rotor.

Each cylinder 82 consists of an inner end portion 88 and a jacket portion 90. The jacket portion 90 is opposed to each other Slits 92 and 94 and also has numerous exhaust openings 96 around its circumference. In a piston 98 is slidably arranged in each cylinder 82. Each piston 98 has a head part 100 and a side part 102. On a transverse pin 106, which is in the side part 102 is attached, a roller 104 is mounted. This rolls on the cam surface 108 of the cam 18 and moves so the piston relative to the cylinder when the rotor rotates. Each piston has a plurality of holes therethrough provided on the circumference of its side part.

Each cylinder is led by an exhaust chamber 112 (Fig. 6) surrounded, on the one hand with the exhaust ports 96, on the other hand communicates with two exhaust pipes 114 and 116.

In the embodiment according to FIG. 4, the head part 100 of the piston 9 8 is made of a material 118 of low thermal conductivity overdrawn. As such a material comes z. B. porcelain or another high temperature resistant ceramic material into consideration. Likewise, the part of the inner surface of the cylinder which forms the combustion chamber 120 of the rotor 74 82 lined with the poorly heat-conducting material 118.

The embodiment of FIG. 5 differs from that of FIG. 4 in that the cylinder 82 'and the Piston 98 'consist entirely of a material with a low coefficient of thermal conduction. For example, has Porcelain has a specific thermal conductivity of about 0.6.

It was also found that stainless steel is very suitable as a material for pistons and cylinders or as a lining 118 is. Stainless steel refers to iron alloys that contain nickel and chromium, with the chromium content 12 to 30%. Stainless steel has a far lower thermal conductivity than cast iron. For example, at room temperature Cast iron has a specific heat conductivity of 0.112, while stainless steel (AISI Type 304) has a heat conductivity of 0.036

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Has. Type 304 contains 18 to 20% chromium and 8 to 12% nickel. The AISI types 3OO of stainless steel have been chosen for proved particularly suitable for the present purpose. In this context, reference is made to the Metals Handbook, Volume 1, Pages 408, 409, 422 and 423 ff, edited by the American Society of Metals.

The cam surface 108 of the cam disk 18 has opposing projections 122 and 124. As from Fig. 2 visible are the projections 122 and 124 with locking surfaces 126 and 128 provided, the center of curvature in the geometric The center of the cam 18 is so that the piston remains stationary at these points.

In operation, fuel is continuously supplied to the nozzles 70 and 72 under pressure. However, the fuel can only run out the nozzles 70 and 72 exit when the nozzles over openings 130 of the rotor 74 with the open inner ends of the cylinders 82 come in contact. At this moment, fuel is injected into the combustion chamber of the cylinder in question The air chamber 54 is under constant overpressure, so that air exits the outlet openings 64 and 66 as long as the recesses 42 and 40 via the openings 130 with the interior of the cylinders concerned are in communication while the rotor revolves around the fixed core 30. Furthermore, the Oil grooves 46 and 48 are supplied with pressurized oil so that a film of oil is formed between the inner surface of the rotor and the outer surface

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of the core part 34 forms. This oil film also serves to seal the injection openings 130 with respect to the environment outside the rotor.

Fig. 2 shows the upper and lower pistons in the ignition position. The rollers of these pistons are located on the paste surfaces of protrusions 126 and 128. After the fuel and air were injected into the cylinder, the Piston guided by the rotation of the rotor along the projection 122 inward, whereby the fuel mixture is compressed became. Ignition is initiated at the point of greatest compression. Before the pressure in the cylinder reaches the prescribed Can exceed limit, the piston is allowed to expand slightly into the past position 126 and he remains in this relative expansion position until the combustion process has ended. After the entire chemical Energy of the propellant has been converted into heat, the piston is allowed to expand and this heat energy into to convert mechanical energy, but only when the entire combustion has ended and all the energy after it has started of the working stroke is available after the detent position.

By the poorly heat-conducting coating 118 or the relevant Material of the parts of the cylinder, the rotor and the piston adjoining the combustion chamber the amount of heat absorbed by these parts is considerable

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degraded. The temperature of the coating 18 rises immediately, but proportionally, during the combustion process little heat is dissipated into the material of the cylinder, the combustion chamber and the piston. When the heat of combustion were allowed to remain on the surface of the coating 118, this relatively small amount of heat would be reflected in the subsequent Increase working strokes so that the temperature would gradually assume an impermissibly high value. Well v / ird but relatively cool fresh air under pressure is constantly supplied to the recesses 40 and 42 and can enter the cylinder occur when the recesses 40 and 42 are in communication therewith via the openings 13o, while the rotor is moving turns. The compressed air entering the cylinder not only flushes the exhaust gases out of the cylinder when the Piston has withdrawn through exhaust ports 96, but the fresh air also supports the cooling of the combustion chamber and the recharging of the cylinder for the next cycle. The one supplied from the environment or from another location that is relatively low in temperature Fresh air is fed into the cylinder in excess, so it is available in larger quantities than it is used to flush the Exhaust gases necessary v / are. As a result, it comes into intimate contact with the lining 118 and carries the heat directly formed there beforehand during the combustion, from the surface of the lining. So the cooling hangs the machine described does not depend on the dissipation of heat

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through the cylinders, but the cylinders can cool down quickly from the inside. This also applies to the embodiment according to FIG. 5.

The temperature of the lining rises during the course of the day of the combustion process briefly on, but the liner isolates the cylinder, injection chamber and piston from the heat of combustion. As soon as the purge air enters the cylinder, it carries the heat away from the ceramic Lining off, so that its temperature drops again quickly. Because less heat is absorbed by the lining during the working stroke a smaller amount of air is required to cool the cylinders again.

After burning, purging and cooling, the air introduced into the cylinder is compressed when the pollen des piston in question approaches the projection 124. The piston is thereby guided inwards and closes the Exhaust ports 96, so that the cylinder located Air can be compressed. At the appropriate time, the fuel is injected into the cylinder when the injectors 70 and 72 are aligned with the respective openings 130, as described above.

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While a machine operating on the principle of the diesel engine has been described above, the invention is equally suitable for machines based on the Otto engine principle, in which the fuel is used together with the combustion air is inserted into the cylinder.

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Claims (5)

Petintanwiit -GMOnchen ^ Munich, the ϊ ■ JU'i ^ T5 Wicienaiayerstrciße 48 T 388 Toi. (ο sa; ^ 9si 25 TOWNSEND ENGINEERING COMPANY in Des Mo ines, Iowa / V. St. A. Claims 1. Internal combustion engine with internal cooling of the combustion chamber by excess scavenging air, characterized in that the combustion chamber is at least partially lined with a poorly heat-conducting material (118). 2. Internal combustion engine according to claim 1, characterized in that the poorly heat-conducting material made of porcelain or another temperature-resistant ceramic material. 3. Internal combustion engine according to claim 1, characterized in that the poorly heat-conducting material consists of stainless steel, 4. Internal combustion engine according to one of the preceding claims, characterized in that the lining is at least the Combustion chamber covers the cylinder and the head of the piston. 5 η q RR π / 1 η ^Γ , π 5. Internal combustion engine according to one of the preceding claims, characterized in that the cylinders (82), cylinder heads (120) and pistons (9 8) at least in the area of the combustion chamber consist of poorly thermally conductive material.